I guess that would work, but there's another way (and I think this is the way they "intended" this to be done) without having to add a "faux" or "ghost" pedal to your layout.
if you have two channel strips in a given patch.
if you go to the "MIDI input" tab, and look at controllers, it'll probably show Input - Expression (11), TRANSFORM, and then Output - Expression (11). So not only can you change cc#s here, but you can transform 'em. Click on the Transform button, "invert" one of the two channel strips. You can adjust the curves for both the channel strips so that you're crossfade works smoothly, or abruptly, whatever you want.
Just an idea